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Commit 6f65360b authored by Charan Teja Reddy's avatar Charan Teja Reddy Committed by Srinivasarao P
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mm/madvise: use mmap_sem lock from passed mm_struct 

Use the mmap_sem lock from passed 'mm' rather than the 'current' as it
is required because of the patchset[1]. The commit f4fa8d93 ("mm:
madvise: fix vma user-after-free") changed the 'mmap_sem' to use from
'current' instead of 'mm' context. Revert it.

Link: [1] https://patchwork.kernel.org/project/linux-mm/patch/20200302193630.68771-2-minchan@kernel.org/

.

Change-Id: Ifc9deb2a5f0775c2bc97c85db3584f61fa3a43ae
Signed-off-by: default avatarCharan Teja Reddy <charante@codeaurora.org>
Signed-off-by: default avatarSrinivasarao P <spathi@codeaurora.org>
parent 9bf32d70

mm/madvise.c

+1 −1
Original line number Diff line number Diff line
@@ -298,7 +298,7 @@ static long madvise_willneed(struct vm_area_struct *vma, 
	get_file(file);

	offset = (loff_t)(start - vma->vm_start)

			+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);

	up_read(&current->mm->mmap_sem);

	up_read(&mm->mmap_sem);

	vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED);

	fput(file);

	down_read(&mm->mmap_sem);